As for crampness...the vamp is like CIAD said...it depends on the figure. Ones with wide shoulders and legs with large packs on the sides do hinder another passenger. Some just fit better than others - sort of like a Slugger tank.

The firebat works best with a female pilot or again a figure with narrow shoulder span. I got a stinger driver to fit - but that just didn't seem correct for me, so I made a female pilot for it. Plus the way I see it - that is a high speed vehicle, so the cockpit has to be crampt.

The D-hawk has plenty of room - especially since the seat is for a 3.75" figure.

All in all...I'm happy with them. Some of them worked out better than others, but overall...the scale of them works very well with 3.75".